Method for computing an energy efficient route
Probe data is analyzed to derive Longitudinal Speed Profiles (LSPs) and an Optimal Longitudinal Speed Profile ( 18 ) for each road segment or link in a digital map network. The Longitudinal Speed Profiles (LSPs) profiles are calculated during defined time spans whereas the Optimal Longitudinal Speed Profile ( 18 ) is based on the LSP for the time span corresponding only to free flow traffic conditions. All of the LSPs can used to create a respective energy cost for each time span, or only the OLSP ( 18 ) can be used (or alternatively the RRDSL 16 or LRRDSL 17 ) to calculate an energy cost for the free flow conditions only. The energy cost can be used to predict the energy required by a vehicle to traverse the link. Navigation software can use the energy cost to plan the most energy efficient route between two locations in the digital map. Sensory signals can be activated if a driver strays from the Optimal Longitudinal Speed Profile ( 18 ) to achieve extremely high levels of energy efficiency.
1. A method for providing energy efficient navigation directions via a navigation device, said method comprising:
obtaining energy cost data associated with one or more predetermined road segments, the energy cost data derived from at least one Longitudinal Speed Profile (LSP) obtained from probe data associated with the one or more predetermined road segments;
calculating, by a processor, one or more routes and an associated energy cost for each of the one or more routes from an origin to a destination based on the obtained energy cost for the one or more predetermined road segments; and
providing, by the processor, a route from the origin to the destination calculated to be the most energy efficient route of the calculated one or more routes based on the energy costs via the navigation device.
2. The method according to claim 1 , wherein the at least one LSP is statistically derived from bundled probe data.
3. The method according to claim 2 , wherein the derivation of the at least one LSP includes determining a given Longitudinal Speed Profile (LSP) individually per direction of travel along the associated road section.
4. The method according to claim 3 , wherein the derivation of the at least one LSP includes determining the given LSP per lane in the direction of travel along the associated road section.
5. The method of claim 1 , wherein the LSP is indexed with respect to a predetermined time period.
6. The method of claim 1 further comprising creating an acceleration profile based on the at least one LSP.
7. The method according to claim 1 , wherein the at least one LSP associated with the one or more predetermined road segments comprises one of: a raw road design speed limit (RRDSL); a legal raw road design speed limit (LRRDSL); or an optimal longitudinal speed profile (OLSP) obtained from probe data associated with the road segment, and wherein the energy cost data for the road segment is derived from the respective RRDSL, LRRDSL or OLSP.
8. The method according to claim 1 , wherein the energy cost data is derived from the at least one LSP on the navigation device.
9. A navigation for device providing energy efficient navigation directions, the navigation device comprising:
a memory; and
a processor, the processor being arranged to:
obtain energy cost data associated with one or more predetermined road segments, the energy cost data derived from at least one Longitudinal Speed Profile (LSP) obtained from probe data associated with the one or more predetermined road segments;
calculate one or more routes and an associated energy cost for each of the one or more routes from an origin to a destination based on the obtained energy cost for the one or more predetermined road segments; and
provide a route from the origin to the destination calculated to be the most energy efficient route of the calculated one or more routes based on the energy costs via the navigation device.
10. The navigation device according to claim 9 , wherein the at least one LSP is statistically derived from bundled probe data.
11. The navigation device according to claim 10 , wherein the derivation of the at least one LSP includes determining a given LSP individually per direction of travel along the associated road section.
12. The navigation device according to claim 11 , wherein the derivation of the at least one LSP includes determining the given LSP per lane in the direction of travel along the associated road section.
13. The navigation device according to claim 9 , wherein the at least one LSP associated with the one or more predetermined road segments comprises one of: a raw road design speed limit (RRDSL); a legal raw road design speed limit (LRRDSL); or an optimal longitudinal speed profile (OLSP) obtained from probe data associated with the road segment, and wherein the energy cost data for the road segment is derived from the respective RRDSL, LRRDSL or OLSP.
14. The navigation device according to claim 9 , wherein the energy cost data is derived from the at least one LSP on the navigation device.